In recent years, a server which provides a game to portable devices via a communication network has been commonly used. The game provided by the server includes one in which multiple players can participate (i.e., a “social game”), in which the players can not only battle and cooperate with each other but also communicate with each other (for example, refer to Japanese Unexamined Patent Publication No. 2005-034303).
As an example of such a social game, a game is known in which a player battles against an enemy character by using, for example, cards (i.e., a “card battle game”) (for example, refer to Japanese Unexamined Patent Publication No. 2008-142352). In a card battle game, by using cards, a player battles against an enemy character created by the game program, while cooperating with a different player. Each player can possess an arbitrary number of cards, and, by using at least one possessed card, forms a set of cards (i.e., a “deck”) to be used for the battle. Each card has parameters such as attack power, defense power, and a health point, and the players reduce the health point value of the enemy character based on the attack power values of the cards which form the deck (hereinafter, referred to as “deck cards”). The enemy character also has parameters similarly to the cards, and, based on the attack power value thereof, reduces the health point values of the deck cards. The players and the enemy character alternately attack each other, and the battle ends when the health point value of the enemy character has fallen to 0, or when the health point value of each deck card has fallen to 0.
FIG. 12 illustrates an example of a battle screen 1000 of a conventional card battle game.
An image 1001 and a health point gauge 1002 of an enemy character are displayed at the top of the screen, while images 1003 and health point gauges 1004 of deck cards are displayed at the bottom of the screen. When a battle starts, proceeding of the battle is displayed in such a manner that the deck cards attack the enemy character one after another, and next, the enemy character attacks a part of the deck cards (for example, the deck cards indicated by a broken line 1005) all at once, and again, the deck cards attack the enemy character one after another. If the player provides an instruction to use a support character (not illustrated), the support character is displayed at the time when the enemy character attacks a part of the deck cards all at once, and then the support character attacked by the enemy character in place of the deck cards is displayed. Then, the battle ends when the health point gauge 1002 of the enemy character has fallen to 0, or when the health point gauges 1004 of the deck cards have fallen to 0, and the outcome of the battle is displayed.